Diagnostic indicators of squamous cell carcinoma

Diagnostic indicators of squamous cell carcinoma:

1. Overlying epidermal dysplasia or tumour arising from the epithelium.

• Squamous cell carcinoma, as the name indicates arises from squamous epithelial cells, the cells in the spinous layer.

Picture shows tumour arising from the overlying epithelium.

2. Single cell/ individual cell keratinisation. 

• An important feature of squamous cells is to produce keratin, which is seen as an intense hyaline appearance.

Picture shows individual cell keratinisation - seen as dense eosinophilic area in the cytoplasm. Note the malignant nuclei.

3. Keratin pearl formation:

• Tumour cells enclosing masses of anucleate keratin (Reminds me of a rose bud!!)
• Seen in well differentiated tumours.

Picture shows keratin pearl - yellow circle;  resembles a rose bud!!
Individual cell keratinisation: green circle.

4. Intercellular bridges:

• As these are epithelial cells and are connected to each other by cell-cell junctions (desmosomes), these can be seen in a tumour arising from squamous cells.

• In a poorly differentiated tumour, where keratin pearls are absent and individual cell keratinisation may not be prominent, the only feature which helps in a morphological diagnosis is intercellular bridges.
• These are better seen in areas of the tumour where there is oedema of the stroma.

In picture, very fine small lines are seen in between two tumour cells, connecting them.

Well differentiated squamous cell carcinoma is the most difficult diagnosis in surgical pathology!!